(1) Industrial Field Utilizing the Invention
The present invention concerns a free-access floor which allows power cables and communications cables to be laid on a floor surface.
(2) Prior Art
In conventional free-access floors consisting of rigid panels, wiring space has for the most part been located only underneath the floor panels. As a result, power cables and communications cables are mixed together in the same underfloor space in the case of such free-access floors.
Meanwhile, no free-access floor which allows the formation of a wiring space above the floor surface has yet been developed. For example, no such disclosure is found in U.S. Pat. No. 3,396,501, U.S. Pat. No. 3,811,237 or U.S. Pat. No. 4,426,824, etc.
Accordingly, in cases where cables are to be moved (e. g., even light cables such as communications cables, etc.), it is necessary to remove and then re-install the floor panels. This leads to difficulties: i. e., the floor panels are heavy, and rattling may result from panels being left loose at the time of re-installation. Ordinarily, specialists are required for such panel removal and re-installation. In order to avoid such problems, undercarpet type cables which are laid on the floor surface have been used. In this case, however, there are restrictions on the cross-sectional shape of the cables and on the number of cables that can be laid. Furthermore, since underfloor wiring is naturally impossible in such a case, there are difficulties in using such a system for the laying of power cables. Moreover, in cases where power cables and communications cables are to be laid mixed together, it is desirable to lay the two types of cables separately using ducts, etc. Conventional free-access floors have not been able to cope successfully with such difficulties and requirements.